The various valves on the “Christmas tree” collectively form the safety control center of the oil well. They work in coordination according to functions such as main control, daily production and emergency maintenance.
Main Control Valves (Safety Core)
Usually a hydraulically driven gate valve located at the top. Its function is to quickly close in an emergency to cut off the connection between the wellhead and the upper process, preventing the accident from expanding. It serves as the primary safety barrier.
Usually a manual gate valve located below the upper main valve. Its function is to act as a secondary safety barrier and provide isolation when the upper main valve requires maintenance. It is not fully open during normal production.
Production Valves (Daily Operation)
Usually a hydraulically driven automatic valve connected to the main oil output pipeline. Its function is to close or regulate the main output channel of oil and gas from the well in emergency situations or during daily operations.
Not a simple on-off valve, but a crucial flow control device. By replacing chokes of different inner diameters, the production rate of the well and the wellhead pressure can be precisely regulated.
Auxiliary Valves (Maintenance and Injection)
Located at the top, operated manually. It is opened when wireline, cable or other downhole operations or pressure measurement is required, and is closed at other times.
Operated manually. It is used for injecting well killing fluid, chemical inhibitors (anti-corrosion, anti-freezing), and other fluids into the well.
During normal production, the upper master valve, lower master valve and production wing valve are open, and the oil and gas are produced after being regulated by the choke. The wax cleaning valve and well-killing wing valve are usually closed. In case of emergency, the system will automatically close in sequence: choke → production wing valve → upper master valve → lower master valve. This sequence can quickly and safely isolate the oil well.
The underwater “Christmas tree” valves used in deep-sea applications have more stringent requirements in addition to the above functions:
Post time: Feb-11-2026
